Folding fin



Nov. 13, 1962 w. w. HAWLEY EI'AL 3,

FOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 1 WILBUR W. HAWLEY DAVIDJ. HAYKIN,Jr.

ATTORNEYS Nov. 13, 1962 w. w. HAWLEY EIAL 3,063,375

VFOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 2 WILBUR W. HAWLEY DAVIDJ. HAYKIN, Jr.

\ ATTORNEYS Nov. 13, 1962 w. w. HAWLEY ETAL 3,0 3,3 5

FOLDING FIN Filed May 19, 1960 3 Sheets-Sheet 3 WILBUR W. HAWLEY DAVID JHAYKIN, Jr

INVENTORS ATTORNEY United States Patent ()1 States of America asrepresented by the Secretary of the Navy Filed May 19, 1960, Ser. No.30,393 3 Claims. (Cl. 102--50) The present invention relates to foldingfins for booster rockets and the like. More particularly, it relates toa fin folding arrangement wherein the fin axis or span extends parallelto the airframe longitudinal axis in a collapsed condition and iserected principally by a rotary movement.

Prior folding fins comprise either a telescoping arrangement or a singlehinge joint which may be located at the fin root or at some point alongthe fin span. Telescoping fins are generally unsatisfactory if subjectedto extremely high aerodynamic loads such as are encountered in transonicand supersonic flight. Hinged fins do not greatly reduce the stowagespace if the fin span exceeds the diameter of the missile. The presentinvention, however, is capable of reducing the required stowage areapractically to the area of a square circumscribing the missile crosssection even though the fin span may be'considerably greater than thelength of one side of the circumscribing square.

Accordingly, it is an object of the present invention to provide amissile structure having collapsible wings or fins.

It is a further object to provide a missile structure in which the finsare collapsed at all times during stowing or handling and are erectedonly upon launching the missile.

Another object of the invention is to provide a folded fin missilestructure in which a large part of the force required to erect the finis supplied by setback upon launching the missile.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of the present invention showing itsapplication to the booster rocket of a missilecombination, the finsbeing shown in fully folded positions;

FIG. 2 is a perspective view of the fin mounting portion of the boosterrocket of FIG. 1 showing the fins shortly after initiation of theerecting operation;

FIG. 3 is a view similar to FIG. 2 except that the fins appear in medialpositions;

FIG. 4 is similar to FIG. 3 except that the fins have progressed verynearly to their final extended positions;

FIG. 5 is a rear view of the booster with the fins shown in thepositions of FIG. 4;

FIG. 6 is a perspective of the rear portion of the booster rocketshowing the fins in fully erect positions;

FIG. 7 is a plan view of the rear portion of the booster showing certainelements of the fin erecting mechanism in phantom; and

FIG. 8 is a partial sectional view taken along the line 8--8 of FIG. 7.

FIG. 1 illustrates the invention as applied to a jettisonable boosterrocket 10 similar to those commonly employed in launching a largevariety of guided missiles. The rocket 10 is supported on a launcherrail 12 by means of shoes 13 and 13'. A missile 14 is detachably securedto the forward end of rocket 10. The missile 14 is designed forsupersonic operation and hence requires a wing of only a small span todeliver the necessary control moments and lift. The booster rockethowever is needed only during the subsonic and transonic portions of themissiles 3,063,375 Patented Nov.'13., 1962 ice flight. Once the missilehas reached a supersonic speed the booter is jettisoned, reducing boththe drag and the weight which would otherwise need to be transported bythe missile. Because of the greater span, the booster fins create a moreseverestorage and handling problem than do the missile fins. For thisreason the invention is illustrated and described as being applied onlyto the booster although obviously it may be applied to the missile finsif desired.

The four booster fins 15 are folded forwardly with their span axisparalleling the booster longitudinal axis and with one surface of'thefin tangent to the body of the booster 1d. The root edge 16 of each fin15 faces aft. The launching shoe 13' is secured to the root edge of theupper fin 15 and for aerodynamic balance a similar shoe may be securedto the lower fin. A skewed actuating rod 18 extends from the interior ofthe rear portion of booster 10 to the fin root edge 16, to which it isrigidly secured, as by welding. The rod 18 serves both to erect the finand to secure it either in a folded or an erected position. A simplerotary motion of the rod 18 causes the attached fin to rotate so thatthe forward tip 19 of the fin moves both outwardly and towards the rearwhile the fin root 16 rotates from a position transverse to thelongitudinal axis of the booster to a position paralleling the boosterlongitudinal axis.

FIGS. 2, 3 and 4 illustrate the effect of rotating rod 13. In FIG. 2, atthe commencement of the erection operation, the fin tip 19 is displacedaft and outwardly from the position shown in FIG. 1. FIG. 3 shows theposition of the fins after motion has proceeded to a more advancedstage. Further rotation of actuating rod 13, from the position of FIG.3, through a total of from the position of FIG. 1, produces thecondition shown in FIGS. 4 and 5. The fins 15 are fully erect, but areoff-set from the missile center line with the root 16 slightly elevatedabove the booster body. The off-set is removed, and the fins 15 arelowered into proper alignment as shown in FIG. 6, simply by retractingactuating rod 18.

The fin actuating mechanism is shown in FIGS. 7 and 8. It should beunderstood that a large contribution to the actuating force is suppliedby the booster set-back forces, since acceleration supplied by thebooster thrust is commonly in the neighborhood of 15 g. Therefore, theprimary function of the actuating mechanism is to move the fins into aslightly unbalanced condition whereafter the inertia of the fins willaccount for the major portion of the force needed to complete theoperation.

The rear portion of the booster includes a nozzle 21, best seen in FIG.7, shrouded by the booster skin 22. The actuating mechanism is enclosedwithin the space provided by the constriction of the nozzle throat andincludes .four actuating cylinders 23, only one of which is shown.Cylinder 23 is pivotally secured to a boss 24 cast on the outer surfaceof nozzle 21. The hydraulic pressure line connections to cylinder 23 arenot shown but it will be understood that a suitable source of hydraulicpower is made available to cylinder 2-3. The piston rod 25 of cylinder23 is pivotally connected to a bell crank 26. The lower end of rod 18 issplined, as seen at 27 in FIG. 8, and crank 26 is provided with teeth sothat rod 18 is constrained to rotate with crank 26 but is free to moveaxially. Rod 18 passes through a guide bushing 28 secured internally ofthe booster. The bushing 28 is provided with a slot 31 through whichextends a guide pin 32 secured to rod 18. A compression spring 33 isfitted over the end of rod 18 and held in place by a cap 34 fixed to theend of rod 18. Spring 33 bears against crank 26 and imparts a thrust torod 18 urging the rod to retract into the booster. Initially, rod 18 isprevented from retraction by pin 32 riding the portion of slot 31 whichextends partially about the circumference of bushing 28. When the pistonrod of cylinder 23 has been extended sufliciently to drive crank 26through 120 and hence to rotate rod 18 an equal amount, pin 3-2 willhave travelled to the portion of slot 31 extending along the axis ofbushing 28. The thrust of spring 33, then unresisted, causes rod 18 towithdraw into the booster. The splined connection of crank 26 to rod 18also permits this desired motion to occur without interference.

FIGS. 7 and 8 illustrate the relative positions of the elements of theactuating mechanism when the fins are in the folded condition of FIG. 1.The fins are retained in this folded position so long as the piston rod25 does not move. When it is desired to erect the fins pressurized fluidis brought to act upon the piston rod, causing it to move from itsinitial position. During the erection operation shown progressively inFIGS. 2, 3 and 4, the piston rod 25 extends, crank 26 rotates and pin 32travels the length of the circumferential portion of slot 31. At thisstage, the fins are in the position of FIGS. 4 and 5. Finally, pin 32,having arrived at the axially extending portion of slot 31, allowsspring 33 to retract rod 18 and move the fins from the position of FIGS.4 and to the position of FIG. 6. A recessed portion 35 of the boosterreceives the launching shoe 13' as the fin is drawn into its final erectposition and thus fairs the booster surface for the reduction of drag.

As best seen in FIG. 7, a portion 36 of the root of fin is cut away sothat the leading edge of the fin will not strike the booster body whenthe fins are approximately in the position of FIG. 3. An island 41, bestseen in FIGS. 3 and 4 and shaped similarly to the cut-away portion 36,is built up from the booster body to provide a smooth fairing of the fininto the booster body. The island structures 41 may be provided with asuitable mechanism for latching the erected fins in place, although therestraint provided by the actuating mechanism is sufiicient for manyapplications.

Obviously, many modifications and variations of the present inventionare possible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A collapsible wing arrangement for aerial vehicles, including avehicle body of generally cylindrical form, a planiform airfoil having aroot edge and a tip edge opposite said root edge, said airfoil beingnormally carried edgewise to the airstream with said root edge securedto said body, a shaft rigidly secured to said root edge oblique to theplane of said airfoil and extending into said vehicle body oblique to aplane perpendicular to the longitudinal axis thereof, said shaft beingmounted within said body for rotational and axial shifting movement andbeing so disposed relative to said two planes that rotation thereof willmove said airfoil from a collapsed position, wherein the plane of saidairfoil is tangent to the vehicle body with said tip ahead of said rootedge along the line of travel of the vehicle, to a position wherein theairfoil is edgewise to the airstream with the root edge thereof spacedfrom said body and with the plane thereof laterally offset from andparallel to a plane including the longitudinal axis of said body, meansfor rotating said shaft, and means for axially retracting said shaftinto said body to thereby shift the plane of said airfoil into said lastmentioned plane.

2. A collapsible wing arrangement as recited in claim 1, wherein saidmeans for rotating said shaft includes a bell crank connected to saidshaft and a hydraulic piston connected between said bell crank and saidvehicle body, said bell crank being so connected with said shaft thatthe latter is constrained to rotate with said crank but is free to shiftaxially, and wherein said last mentioned means includes a cap afiixed tothe free end of said shaft and a resilient means compressed between saidcap and said bell crank.

3. A folded fin configuration for booster rockets and the like,comprising a rocket body, a stabilizing airfoil generally planiform andnormally carried edgewise to the airstream with its root end secured tosaid body, a rotatable shaft extending from the interior of said bodyaskew to a plane perpendicular to the longitudinal axis thereof andoblique to the plane of said airfoil, said shaft being rigidly securedto the root end of said airfoil for rotating said airfoil from a firstposition, wherein said airfoil is carried tangent to said body andextends longitudinally therewith, to a second position, wherein saidairfoil is presented edgewise to the direction of the airstream with theroot end thereof adjacent said body, means for rotating said shaft, andmeans for retracting said shaft to translate the position of said#airfoil into a plane containing the longitudinal axis of said body.

References Cited in the file of this patent UNITED STATES PATENTS1,166,879 Alard Jan. 4, 1916 2,427,217 Lebherz et al. Sept. 9, 19472,940,688 Bland June 14, 1960

